The present invention concerns a method and apparatus for the control of auxiliary air nozzle blowers used to insert and transport weft threads in weaving looms.
For air jet weaving looms, a method is already known whereby the insertion of a weft thread is mainly achieved by means of several jet nozzles including main nozzles located at the inlet of the shed and auxiliary nozzles distributed along the shed. The use and general technical result obtained by the application of auxiliary nozzles is generally known and described in detail in the German Pat. No. 1.535.454.
A method is also generally known whereby the auxiliary nozzles can be sequentially or in other words, one after the other, controlled within relatively short time intervals. According to another still well-known method, the sequential control also includes "after blowing" with a few auxiliary nozzles in order to support the thread inserted in the shed.
According to another known method, the auxiliary nozzles are controlled by means of various methods, for instance, by modifying timing of the switching-on moments, the switching-on time intervals, the working pressure and all as a function of, for instance, the weft pattern of the measured weft speed.
It is also known that some auxiliary nozzles can be alternatively via valves having various pressures varied in accordance with the weft pattern.
It is also well known that different auxiliary nozzles can be supplied with different pressures.
In all these known methods the air stream in the shed created by high quality jets, i.e., high pressure or high velocity air flowing from the auxiliary nozzles. As, however, the guiding of the weft as well as the application of a pulling force on the weft are achieved by means of high energy air jets, the disadvantage of a huge air consumption characterizes all the aforesaid methods.